Atomic H/C And O-C Ratio Essay

3.3. Atomic H/C and O/C ratio
The Atomic H/C and O/C for heavy oil obtained from different HDO solvent is presented in Fig. 2. Conversion and removal of unstable acid, aldehyde, sugar and water might reduce the O/C ratio. The atomic ratio was calculated by the value of water excluded heavy oil, since H/C ratio could also decrease, despite hydrogenation. Compared with that of bio-oil (0.9), atomic O/C ratio was effectively reduced via HDO reaction (0.2-0.8), H/C ratio reduced 1.0-2.0 (compared with that of bio-oil; 2.1) due to the deoxygenation or dehydration. In case of using polar protic ethanol, O/C ratio steadily decreased from 0.6 to 0.3 with increasing temperaturem while H/C ratio maintained the value of 0.1. However, polar aroptic acetone
Acetic acid, which was major factor of increase acidity, instability as well as decrease HHV, effectively converted into acetic acid, ethyl ester, or was separated in light oil phase when using ethanol as solvent. When ethanol was hydrodeoxygenated with noble metal catalyst, 72.4 % of ethanol converted into gas and only 27.6 % was left. It contained a certain level of ethyl ester (such as acetic acid, ethyl ester and propanoic acid, ethyl ester). Therefore, ethanol was concerned to the HDO reaction as co-reactant (convert acid in bio-oil into ester) and enhanced acidity and stability of
The carbon recovery in the heavy oil is 55.3, 72.8, and 64.7% in ethanol, acetone, and ether, respectively. Acetone contributed to the highest carbon recovery (72.8%) in the heavy oil, while ether transferred 18.3% of carbon into the char. The highest carbon recovery might be due to the promoting demethoxylation and anti-promoting dealkyltaion features of polar aprotic solvent (acetone). Esterification which was effective in ethanol solvent could reduce the carbon recovery due to the modification, not removal of oxygen-containing compounds